Flavoring compositions containing alkyl esters of 2-methyl-4-pentenoic acid

ABSTRACT

Methods are described for adding 2-methyl-4-pentenoic acid and/or C 2  -C 6  alkyl esters thereof to foodstuffs, chewing gums or medicinal products in order to impart sweet, fruity, strawberry, winey-cognac, pineapple-like, pear, green and/or apple-like aromas and tastes; with cooked strawberry jam undertones to said foodstuffs, chewing gums or medicinal products.

This application is a continuation-in-part of U.S. application for Letters Patent Ser. No. 490,718 filed on July 22, 1974 now U.S. Pat. No. 3,907,718.

BACKGROUND OF THE INVENTION

The present invention relates to 2-methyl-4-pentenoic acid and C₂ -C₆ alkyl esters thereof and novel compositions and processes using such 2-methyl-4-pentenoic acid and esters to alter the flavor of foodstuffs, chewing gums and medicinal products.

There has been considerable work performed related to substances which can be used to impart (or enhance) flavors to (or in) various types of foodstuffs, chewing gums and medicinal products. These substances are used to diminish the use of natural materials, some of which may be in short supply and to provide more uniform properties in the finished product. Sweet, fruity, strawberry, winey-cognac, cooked strawberry jam, pineapple-like, pear, green and apple-like aromas as well as tastes are particularly desirable for manay uses in foodstuff flavors.

U.S. Pat. No. 3,499,769 issued on Mar. 10, 1970 discloses processes for imparting a fresh fruity flavor (particularly strawberry flavor) to foods by adding a small amount of 2-methyl-2-pentenoic acid to the foodstuff. In U.S. Pat. No. 3,499,769 it is emphasized that the basic nuance imparted by the 2-methyl-2-pentenoic acid is a "berry" flavor.

Quite unexpectedly, the 2-methyl-4-pentenoic acid and esters thereof of the instant invention have properties different in kind from the 2-methyl-2-pentenoic acid of U.S. Pat. No. 3,499,769 which is only fruity and strawberry-like and does not have the sweet, fruity, winey-cognac, pineapple-like, pear, green and apple-like aroma and taste qualities of the 2-methyl-4-pentenoic acid and esters thereof of the instant invention.

Arctander, "Perfume and Flavor Chemicals", 1969 discloses the use in perfume compositions and flavors of 4-pentenoic acid, thus:

" . . . only rarely used in perfume compositions mainly on fruity bases and certain artificial essential oils.

It finds use in flavors on account of its sour-caramellic taste, pleasant at levels below 10 ppm, and including an almost sweet aftertaste. Higher concentrations have acrid taste and repulsively acid odor, pungent and irritating.

Traces, equivalent to 1 to 5 ppm, are used in imitation butter flavor and in various fruit flavor complexes, e.g., apple, pinapple, apricot and strawberry."

at Volume II, No. 2452. Artctander also discloses the use of trans-2-methyl-2-butenoic acid (tiglic acid) at Vol. II, No. 2949 in perfumery:

"Spicy-rooty, sweet-sour herbaceous odor of moderate tenacity."

and the use of cis-2-methyl-2-butenoic acid (angelic acid) and alkyl esters thereof in perfumes and flavors at Vol. I, No. 238.

The alkenoic acids and esters thereof of the prior art are considered to be different in kind from the 2-methyl-4-pentenoic acid and C₂ -C₆ alkyl esters thereof of the instant invention insofar as their organoleptic properties are concerned.

Rossi and Ingrosse, Chem.Abstr. 69, 95851(g) (Abstract of Gazz.Chim.Ital. 98(7), 866-83 (1968) ) discloses the preparation of 2-methyl-4-pentenoic acid by reacting 3-chlor-propene-1 with 1,1-dicarboethoxyethane.

De Moura Campos and de Amarat, Chem.Abstr. 63: 4159(e) (Abstract of J.Arch.Pharm. 298(2), 92-100 (1965) discloses the preparation of 2-methyl-4-pentenoic acid by the following reaction sequence: ##SPC1##

Trace and Gurante, Chem.Abstr. 55:14324(i) (Abstract of Rend.Inst.Lombardo Sci. Pt.I, Classe Sci. Mat. e Nat., 94A, 309-330 (1960) discloses a process for preparing 2-methyl-4-pentenoic acid by reacting 2-cyclopropyl-propionic acid with HBr.

Adler and Brachel Chem.Abstr. 57: 2042(d) (Abstract of Ann. 651, 141-53 (1962) sets forth a process for giving 12% yields of methyl-2-methyl-4-pentenoate by means of the following reaction: ##SPC2##

These processes as well as other processes of the prior art have not been found to have lower commercial feasibility in view of the complexity and/or cost of carrying out the particular reaction involved; as distinguished from the novel process of our invention.

THE INVENTION

It has now been discovered that novel solid and liquid foodstuff and flavoring compositions having sweet, fruity, strawberry, winey-cognac, pinapple-like, pear, green, and apple-like aromas and tastes with cooked strawberry jam undertones be provided by the utilization of 2-methyl-4-pentenoic acids and/or C₂ -C₆ alkyl esters thereof having the generic formula: ##SPC3##

wherein R is hydrogen, or one of C₂ -C₆ alkyl in foodstuffs, chewing gums and medicinal products.

The 2-methyl-4-pentenoic acid and C₂ -C₆ alkyl esters thereof, so useful, may be produced according to the process comprising the steps of first reacting 1,1,1-triethoxy-propane with 2-propenol-1 to form ethyl-2-methyl-4-pentenoate; then, in the alternative, (i) using the thus-formed ethyl-2-methyl-4-pentenoate as such for its own organoleptic characteristics as a flavor adjuvant or enhancer, or (ii) saponifying the ethyl-2-methyl-4-pentenoate with base to form a salt of 2-methyl-4-pentenoic acid and then acidifying the salt of 2-methyl-4-pentenoic acid with acid to form 2-methyl-4-pentenoic acid itself and either using the said 2-methyl-4-pentenoic acid for its own organoleptic characteristics as a flavor adjuvant or enhancer or esterifying the 2-methyl-4-pentenoic acid with a C₃ -C₆ alkanol to form a C₃ -C₆ alkyl ester of 2-methyl-4-pentenoic acid or (iii) reacting the ethyl-2-methyl-4-pentenoate with a C₃ -C₆ lower alkanol to form a C₃ -C₆ lower alkyl 2-methyl-4-pentenoate.

The 2-methyl-4-pentenoic acid and C₂ -C₆ alkyl esters thereof may also be produced according to the process comprising the steps of first reacting a 1,1,1-trilower alkoxy propane with 2-propynol-1 to form an alkyl-2-methyl-3,4-pentadienoate; then, in the alternative, either (i) hydrogenating with hydrogen gas the thus-formed alkyl-2-methyl-3,4-pentadienoate in the presence of a palladium-on-carbon catatyst or a palladium-on-calcium carbonate catalyst, thereby forming a reaction mixture containing alkyl-2-methyl-4-pentenoate (such as the ethyl, isobutyl or hexyl ester) and using this material as such for its own organoleptic characteristics as a flavor adjuvant or enhancer, or (ii) recovering the alkyl-2-methyl-4-pentenoate and using the thus-recovered material for its own organoleptic characteristics or (iii) carrying out an ester interchange reaction with the thus-formed alkyl-2-methyl-4-pentenoate by reaction with a lower alkanol in the presence of a protonic acid catalyst and using the thus-formed second alkyl-2-methyl-4-pentenoate as such for its own organoleptic characteristics as a flavor adjuvant or enhancer, or (iv) saponifying the alkyl-2-methyl-4-pentenoate with base to form a salt of 2-methyl-4-pentenoic acid and then acidifying the salt of 2-methyl-4-pentenoic acid with acid to form the 2-methyl-4-pentenoic acid itself and either using the said 2-methyl-4-pentenoic acid for its own organoleptic characteristics as a flavor adjuvant or enhancer, or esterifying the 2-methyl-4-pentenoic acid with a C₃ -C₆ alkanol to form a C₃ -C₆ alkyl ester of 2-methyl-4-pentenoic acid.

The 2-methyl-4-pentenoic acid and C₂ -C₆ lower alkyl esters of 2-methyl-4-pentenoic acid of our invention having the generic formula: ##SPC4##

wherein R is hydrogen, or one of C₂ -C₆ alkyl are intended to include singly, and in admixture the two stereoisomers of 2-methyl-4-pentenoic acid and its C₂ -C₆ esters, having the structures: ##SPC5##

wherein R is hydrogen or C₂ -C₆ lower alkyl.

One process for producing the chemical compounds useful in practicing our invention involves the steps of:

a. First reacting 1,1,1-triethoxypropane with 2-propenol-1 in the presence of a phosphoric acid catalyst to form ethyl-2-methyl-4-pentenoate. The reaction temperature range is 100°-225°C with a range of 140°-180°C being preferred. The mole ratio of reactants preferred is 1:1, with a large excess of 2-propenol-1 undesirable and a large excess of triethoxypropane being uneconomical. The reaction time is inversely dependent upon the temperature of reaction. Thus, for example, where the temperature range of reaction is 165°-185°C, the reaction time is approximately three (3) hours. As stated, supra, the reaction product, ethyl-2-methyl-4-pentenoate may be used as is, or it may further be reacted as in step (b) or (c), set forth infra; but in any event, the reaction product is "worked-up" by first neutralizing the acid catalyst, the phosphoric acid, using base (e.g., sodium bicarbonate) and then fractionally distilling the reaction product.

b. If desired, the resulting ethyl-2-methyl-4-pentenoate may be converted into 1-methyl-4-pentenoic acid by the standard saponification and acidification reactions. The saponification is preferably caried out using strong aqueous base, e.g., 50% aqueous sodium hydroxide or 50% aqueous potassium hydroxide admixed with methanol. After acidification of the resulting salt of 2-methyl-4-pentenoic acid (e.g., the sodium or potassium salt) using mineral acid (e.g., 6 molar aqueous hydrochloric acid) the 2-methyl-4-pentenoic acid is extracted from the aqueous phase using an organic solvent such as toluene. The organic solvent is then stripped from the acid and the acid is fractionally distilled. The resulting acid may be used as such, or it may, if desired be esterified with a C₃ -C₆ alkanol to form an ester of 2-methyl-4-pentenoic acid.

c. If desired, the ethyl-2-methyl-4-pentenoate produced as set forth in (a), supra, may be converted into another ester, a C₃ -, C₄ -, C₅ - or C₆ - ester of 2-methyl-4-pentenoic acid, by reaction with a C₃ -, C₄ -, C₅ - or C₆ - alkanol in the presence of a protonic acid catalyst at a temperature in the range of 100°-170°C. The preferable temperature depends upon the particular alkanol used; e.g., about 110°C in the case of isobutyl alcohol; and 140°-150°C in the case of n-hexanol. The preferred catalyst is paratoluene sulfonic acid.

The foregoing series of reactions may be illustrated as follows: ##SPC6##

wherein R' is C₃ -C₆ lower alkyl.

A second process for producing the chemical compounds useful in practicing our invention involves the steps of:

a. First reacting a 1,1,1,-trialkoxy propane (such as 1,1,1-triethoxy propane, or 1,1,1-trihexyloxy propane) with 2-propynol-1 in the presence of a propionic acid catalyst thereby forming an alkyl-2-methyl-3,4-pentadienoate. The reaction temperature range is 120°-180°C with a range of 145°-150°C being preferred. The mole ratios of reactants preferred is 1:1 with a slight excess of either reactant permissible. A large excess of 2-propynol-1 is undesirable, and a large excess of the trialkoxy propane is uneconomical. The percentage of propionic acid catalyst may vary from 1 up to 3%, but a 2% concentration of catalyst is preferred. Since the reaction temperature is in the range of 120°-180°C higher pressures of reaction are required for the carrying out of the reaction, and, accordingly, pressures of from 30 up to 100 psig are used. The reaction time is inversely dependent on the temperature of reaction. Thus, for example, where the temperature range of reaction is 150°- 160°C, the reaction time is approximately 3 hours. The reaction time period varies between 2 and 6 hours, and a reaction time of 3-4 hours is preferred. The reaction product, the alkyl-2-methyl-3,4-pentadienoate, is then worked-up and this work-up operation is performed by first, if necessary, washing out the excesss trialkyl orthopropionate reactant by washing with a dilute (e.g., 5%) hydrochloric acid solution. The acid is then neutralized by use of a sodium bicarbonate wash, and the reaction mass is then fractionally distilled.

b. The resulting alkyl-2-methyl-3,4-pentadienoate is then reacted with hydrogen in the presence of a palladium-on-carbon catalyst or a "Lindlar" catalyst (palladium-on-calcium carbonate). The percentage of palladium on carbon or on calcium carbonate varies from about 2% up to about 7% with a percentage of palladium-on-carbon or on calcium carbonate being preferred to be about 5%. The temperature of reaction for this hydrogenation may vary from about 10°C up to about 50°C with a preferred reaction temperaturea of 25°-35°C. Since the reaction is exothermic, it is usually necessary to provide external cooling to the reaction mass during the course of the reaction. The pressure of hydrogen over the reaction mass may vary from about 5 psig up to about 50 psig, with the most preferred pressure being 20 psig. It has been found that pressures above 20 psig give rise to larger amounts of undesired side products. The hydrogenation reaction may be carried out in the presence of or in the absence of a solvent. When a solvent is used, it is required that it be an inert (non-reactive) solvent such as isopropyl alcohol, hexane or ethanol, with the alkyl moiety of the alcohol solvent being the same as the alkyl moiety of the alkoxy group of the ester being hydrogenated. If a solvent is used, it is preferred that the mole ratio of solvent:pentadienoate ester be approximately 1:1. The percentage of catalyst in the reaction mass may vary from 0.125% up to about 2.0% with a percentage of catalyst of about 0.25% being preferred. When using a Lindlar catalyst, the hydrogenation reaction produces a mixture of alkyl-2-methyl-cis-3-pentenoate and alkyl-2-methyl-4-pentenoate in the ratio of from about 6:4 up to about 7:3. As a result, the desired alkyl-2-methyl-4-pentenoate for use in the instant invention may, if desired, be enriched with respect to the alkyl-2-methyl-cis-3-pentenoate by means of fractional distillation or the mixture resulting may be used as such for its organoleptic properties as a flavor adjuvant or enhancer for use in foodstuffs, medicinal products or chewing gum. Where the catalyst used is palladium-on-carbon rather than a Lindlar catalyst (palladium on-calcium carbonate), a mixture of alkyl-2-methyl-cis-3-pentenoate, alkyl-2-methyl-4-pentenoate and alkyl-2-methyl-pentanoate is formed which may be used as such for its organoleptic properties as a flavor adjuvant or enhancer for foodstuffs, chewing gum and medicinal products or which may be separated as by means of fractional distillation. In any event, at the end of the hydrogenation reaction, the reaction mass is filtered in order to separate catalyst from liquid phase desired product, and the filtrate is distilled using a fractional distillation column operated under vacuum.

c. If desired, the resulting alkyl-2-methyl-4-pentenoate and other esters which have not been separated therefrom after the hydrogenation reaction may be converted into 2-methyl-4-pentenoic acid and other acids by means of standard saponification and acidification reactions. The saponification is preferably carried out using strong aqueous base, e.g., 50% aqueous sodium hydroxide or 50% aqueous potassium hydroxide admixed with methanol. After acidification of the resulting salt of 2-methyl-4-pentenoic acid (e.g., the sodium or potassium salt) using mineral acid), the 2-methyl-4-pentenoic acid is extracted from the aqueous phase using an organic solvent such as diethyl ether. The organic solvent is then stripped from the acid, and the acid is fractionally distilled. The resulting acid may be used as such or it may, if desired, be esterified with a C₃ -C₆ alkanol to form an ester of 2-methyl-4-pentenoic acid.

d. If desired, the mixture of esters including the alkyl-2-methyl-4-pentenoate ester produced as set forth in (b) supra, may be converted into other esters, such as a C₃, C₄, C₅ or C₆ ester of 2-methyl-4-pentenoic acid by reaction with a C₃, C₄, C₅ or C₆ alkanol in the presence of a protonic acid catalyst at a temperature in the range of 100°-170°C. The preferred temperature depends upon the particular alkanol used; e.g., about 110°C in the case of isobutyl alcohol; and 140°-150°C in the case of n-hexanol. The preferred catalyst is paratoluene sulfonic acid.

The foregoing series of reactions may be illustrated as follows: ##SPC7## ##SPC8##

wherein R is C₂ -C₆ alkyl and M is alkalic metal.

Examples of specific reaction products, the uses of which are contemplated within the scope of our invention, and their respective organoleptic properties are set forth in the following table:

    Compound       Flavor Properties                                               ______________________________________                                         Ethyl-2-methyl-4-                                                                             At 0.05 ppm, fresh, sweet,                                      pentanoate     fruity; at 0.1 ppm, very                                                       pleasant strawberry, winey;                                                    at 0.2 ppm, wine, pineapple-                                                   like; at 0.5 ppm, strawberry,                                                  apple, fruity; at 1 ppm,                                                       green, fruity; at 2 ppm,                                                       green, apple.                                                   2-Methyl-4-pentenoic                                                                          Cooked strawberry jam type                                      acid           aroma and taste at 10 ppm.                                      Isobutyl-2-methyl-4-                                                                          At 5 ppm, fruity, pineapple                                     pentenoate     and strawberry aroma and                                                       fruity, pineapple, straw-                                                      berry and sweet taste.                                          n-Hexyl-2-methyl-4-                                                                           At 5 ppm, pear and green                                        pentenoate     aroma and taste notes.                                          ______________________________________                                    

When the 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof of our invention are used as flavor adjuvants for altering the flavor of foodstuffs, medicinal products and chewing gums, the nature of the co-ingredients included with the said 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof in formulating the product composition will also serve to alter the organoleptic characteristics of the ultimate foodstuff, medicinal product or chewing gum treated therewtih.

As used herein in regard to flavors, the term "alter" in its various forms means "supplying or imparting flavor character or note to otherwise bland, relatively tasteless substances or augmenting the existing flavor characteristic where a natural flavor is deficient in some regard or supplementing the existing flavor impression to modify its quality, character or taste."

As used herein, the term "foodstuff" includes both solids and liquids ingestible materials which usually do, but need not, have nutritional value. Thus, foodstuffs include soups, convenience foods, beverages, diary products, candies, vegetables, cereals, soft drinks, snacks and the like.

As used herein, the term "medicinal product" includes both solids and liquids which are ingestible non-toxic materials which have medicinal value such as cough syrups, cough drops, aspirin, chewable medicinal tablets and toothpaste.

The term "chewing gum" is intended to mean a composition which comprises a substantially water-insoluble, chewable plastic gum base such as chicle, or substitutes therefore, including jelutong guttakay, rubber or certain comestible natural or synthetic resins or waxes. Incorporated with the gum base in admixture therewith may be plasticizers or softening agents, e.g., glycerine; and a flavoring composition which incorporates the alkyl-2methyl-4-pentenoate or 2-methyl-4-pentenoic acid of our invention, and in addition, sweetening agents which may be sugars, including sucrose or dextrose and/or artificial sweeteners such as cyclamates or saccharin. Other optional ingredients may also be present.

Substances suitable for use herein as co-ingredients or flavoring adjuvants are well known in the art for such use being extensively described in the relevant literature. Apart from the requirement that any such material be "ingestibly" acceptable and thus non-toxic or otherwise non-deleterious nothing particularly critical resides in selection thereof. Accordingly, such materials which may in general be characterized as flavoring adjuvants or vehicles comprise broadly stabilizers, thickeners, surface active agents, conditioners, other flavorants and flavor intensifiers.

Stabilizer compounds include preservatives, e.g., sodium chloride; antioxidants, e.g., calcium and sodium ascorbate, ascorbic acid, butylated hydroxy-anisole (mixture of 2 and 3 tertiary-butyl-4-hydroxy-anisole), butylated hydroxy toluene (2,6-di-tertiary-butyl-4-methyl phenol), propyl gallate and the like and sequestrants, e.g., citric acid.

Thickener compounds include carriers, binders, protective colloids, suspending agents, emulsifiers and the like, e.g., agaragar, carrageenan; cellulose and cellulose derivatives such as carboxymethyl cellulose and methyl cellulose; natural and synthetic gums such as gum arabic, gum tragacanth; gelatin, proteinaceous materials; lipids; carbohydrates; starches pectins, and emulsifiers, e.g., mono-and diglycerides of fatty acids, skim milk powder, hexoses, pentoses, disaccharides, e.g., sucrose corn syrup and the like.

Surface active agents include emulsifying agents, e.g., fatty acids such as capric acid, caprylic acid, palmitic acid, myristic acid and the like, mono-and diglycerides of fatty acids, lecithin, defoaming and flavor-dispersing agents such as sorbitan monostearate, potassium stearate, hydrogenated tallow alcohol and the like.

Conditioners include compounds such as bleaching and maturing agents, e.g., benzoyl peroxide, calcium peroxide, hydrogen peroxide and the like; starch modifiers such as peracetic acid, sodium chlorite, sodium hypochlorite, propylene oxide, succinic anhydride and the like, buffers and neutralizing agents, e.g., sodium acetate, ammonium bicarbonate, ammonium phosphate, citric acid, lactic acid, vinegar and the like; colorants, e.g., carminic acid, cochineal, turmeric and curcuma and the like; firming agents such as aluminum sodium sulfate, calcium chloride and calcium gluconate; texturizers, anti-caking agents, e.g., aluminum calcium sulfate and tribasic calcium phosphate; enzymes; yeast foods, e.g., calcium lactate and calcium sulfate; nutrient supplements, e.g., iron salts such as ferric phosphate, ferrous gluconate and the like, riboflavin, vitamins, zinc sources such as zinc chloride, zinc sulfate and the like.

Other flavorants and flavor intensifiers include organic acids, e.g., acetic acid, formic acid, 2-hexenoic acid, benzoic acid, n-butyric acid, caproic acid, caprylic acid, cinnamic acid, isobutyric acid, isovaleric acid, alpha-methyl-butyric acid, propionic acid, valeric acid, 2-methyl-2-pentenoic acid, and 2-methyl-3-pentenoic acid; ketones and aldehydes, e.g., acetaldehyde, acetophenone, acetone, acetyl methyl carbinol, acrolein, n-butanal, crotonal, diacetyl, beta, beta-dimethyl-acrolein, n-hexanal, 2-hexenal, cis-3-hexenal, 2-heptanal, 4-(p-hydroxyphenyl)-2-butanone, alpha-ionone, beta-ionone, methyl-3-butanone, 2-pentanone, 2-pentenal and propanal; alcohols, such as 1-butanal, benzyl alcohol, 1-borneol, trans-2-buten-1-ol, ethanol, geraniol, 1-hexanal, 2-heptanol, trans-2-hexenol-1, cis-3-hexen-1-ol, 3-methyl-3-buten-1-ol, 1-pentenol, 1-penten-3-ol, p-hydroxyphenyl-2-ethanol, isoamyl alcohol, isofenchyl alcohol, phenyl-2-ethanol, alpha-terpineol, cis-terpineol hydrate; esters, such as butyl acetate, ethyl acetate, ethyl acetoacetate, ethyl benzoate, ethyl butyrate, ethyl caproate, ethyl cinnamate, ethyl crotonate, ethyl formate, ethyl isobutyrate, ethyl isovalerate, ethyl alpha-methylbutyrate, ethyl propionate, ethyl salicylate, trans-2-hexenyl acetate, hexyl acetate, 2-hexenyl butyrate, hexyl butyrate, isoamyl acetate, isopropyl butyrate, methyl acetate, methyl butyrate, methyl caproate, methyl isobutyrate, alpha-methylbutyrate, propyl acetate, amyl acetate, amyl butyrate, benzyl salicylate, dimethyl anthranilate, ethyl methylphenylglycidate, ethyl succinate, isobutyl cinnamate and terpenyl acetate; essential oils, such as jasmine absolute, rose absolute, orris absolute, lemon essential oil, bulgarian rose, yara yara, natural raspberry oil and vanilla; lactones; sulfides, e.g., methyl sulfide and other material such as maltol, acetoin and acetals (e.g., 1,1-diethoxyethane, 1,1-dimethoxyethane and dimethoxymethane.

The specific flavoring adjuvant selected for use may be either solid or liquid depending upon the desired physical form of the ultimate product, i.e., foodstuff, chewing gum or medicinal product, whether simulated or natural, and should, in any event, be capable of providing an environment in which the 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof can be dispersed or admixed to provide a homogeneous medium. In addition, selection of one or more flavoring adjuvants, as well as the quantities thereof, will depend upon the precise organoleptic character desired in the finished product. Thus, in the case of flavoring compositions, ingredient selection will vary in accordance with the foodstuff to which the flavor and aroma are to be imparted. In contradistinction, in the preparation of solid products, e.g., simulated foodstuffs, ingredients capable of providing normally solid compositions should be selected such as various cellulose derivatives.

As well be appreciated by those skilled in the art, the amount of 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof employed in a particular instance can vary over a relatively wide range whereby to its desired organoleptic effects having reference to the nature of the product are achieved. Thus, correspondingly, greater amounts would be necessary in those instances wherein the ultimate food composition or chewing gum or medicinal product to be flavored is relatively bland to the taste, whereas relatively minor quantities may suffice for purposes of enhancing the composition merely deficient in natural flavor or aroma. The primary requirement is that the amount selected to be effective, i.e., sufficient to alter the organoleptic characteristics of the parent composition, whether foodstuff per se or flavoring composition.

The use of insufficient quantities of 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof will, of course, substantially vitiate any possibility of obtaining the desired results while excess quantities prove needlessly costly and in extreme cases, may disrupt the flavor-aroma balance, thus proving selfdefeating. Accordingly, the terminology "effective amount" and "sufficient amount" is to be accorded a significance in the context of the present invention consistent with the obtention of desired flavoring effects.

Thus, and with respect to ultimate food compositions, chewing gum compositions and medicinal products, it is found that quantities of 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof ranging from a small but effective amount, e.g., 0.03 parts per million up to about 20 parts per million by weight based on total composition are suitable. Concentrations in excess of the maximum quantity stated are not normally recommended since they fail to prove commensurate enhancement of organoleptic properties. In those instances wherein the 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof is added to the foodstuff as an integral component of a flavoring composition, it is, of course, essential that the total quantity of flavoring composition employed be sufficient to yield an effective 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof concentration in the foodstuff product.

Food flavoring compositions, chewing gum flavoring compositions and medicinal product flavoring compositions prepared in accordance with the present invention preferably contain the 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof in concentrations ranging from about 0.25% up to about 15% by weight based on the total weight of said flavoring composition.

The compositions described herein can be prepared according to conventional techniques well known as typified by cake batters and fruit drinks and can be formulated by merely admixing the involved ingredients within the proportions stated in a suitable blender to obtain the desired consistency, homogeneity of dispersion, etc. Alternatively, flavoring compositions in the form of particulate solids can be conveniently prepared by mixing the 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof with for example gum arabic, gum tragacanth, carrageenan and the like, and thereafter spray-drying the resultant mixture whereby to obtain the particular solid product. Pre-prepared flavor mixes in powder form, e.g., a fruit-flavored powder mix are obtained by mixing the dried solid components, e.g., starch, sugar, and the like and 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof in a dry blender until the requisite degree of uniformity is achieved.

It is presently preferred to combine with the 2-methyl-4-pentenoic acid or C₂ -C₆ alkyl ester thereof the following adjuvants:

p-Hydroxybenzylacetone;

Geraniol;

Maltol;

Ethyl methyl phenyl glycidate;

Benzyl acetate;

Vanillin;

Methyl cinnamate;

Ethyl pelargonate;

Methyl anthranilate;

Isoamyl acetate;

Alpha ionone;

Ethyl butyrate;

Gamma-undecalactone;

Naphthyl ethyl ether;

Diacetyl;

Ethyl acetate;

Anethole;

Isoamyl butyrate;

Cis-3-hexenol-1;

2-Methyl-2-pentenoic acid;

Elemecine (4 -allyl-1,2,6-trimethoxy benzene);

Isoelemecine (4-propenyl-1,2,6-trimethoxy benzene)

The following examples are given to illustrate embodiments of the invention as it is presently preferred to practice it. It will be understood that these examples are illustrative, and the invention is not to be considered as restricted thereto except as indicated in the appended claims. All parts and percentages given herein are by weight unless otherwise specified.

EXAMPLE I Preparation of ethyl-2-methyl-4-pentenoate

To a 2 liter autoclave, the following materials are added:

    Triethyl orthopropionate                                                                            495 g                                                     (1,1,1-triethoxypropane)                                                                            (2.4 moles)                                               Allyl alcohol        140 g                                                                          (2.4 moles)                                               Phosphoric acid (85%)                                                                               12 g                                                 

The autoclave is sealed and the mixture is heated with stirring at 165°-185°C for a period of 3 hours.

The autoclave is then opened and 12.6 g sodium bicarbonate is added to the reaction mass in order to neutralize the phosphoric acid. 30 g Primol (a registered trademark for mineral oil manufactured by the Exxon Co. of Linden, N.J.) is then added as a still base, and the reaction mass is fractionally distilled on a 1 × 20 inches packed Goodloe distillation column (i) at atmospheric pressure and 129°C (yielding a mixutre of ethanol and ethyl propionate (245 g) and (ii) at 40 mm Hg. pressure and 75°C (yielding 264 g of ethyl-2 -methyl-4-pentenoate. Yield, based on triethyl orthopropionate used, 73.5%.

Mass spectral analysis: m/e = 69, 41, 29, 27 39 and 68.

    NMR Analysis    Interpretation                                                 ______________________________________                                                         H                                                              1.16 ppm (d)    CH.sub.3 --C--C--                                                              ∥                                                                     O                                                                                             6H                                              1.20 (t)        CH.sub.3 --CH.sub.2 --O--C--                                                    ∥                                                                    O                                                              2.64-2.08 (m)   =C--CH.sub.2 + HC--                                                                           3H                                                              ∥                                                                     O                                                              4.12 (q)        Me--CH.sub.2 --O--C--                                                                         2H                                                              ∥                                                                     O                                                              5.18-4.98 (m)   HC=CH.sub.2    2H                                              5.98-5.56 (m)   HC=CH.sub.2    1H                                              IR Analysis                                                                     915 cm.sup.-.sup.1                                                            1015                                                                           1090                                                                           1140                                                                           1175                                                                           1225                                                                           1240                                                                           1380                                                                           1460                                                                           1730                                                                           2940                                                                           2980                                                                           ______________________________________                                          The NMR spectrum is illustrated in FIG. 1.                                     The IR spectrum is illustrated in FIG. 2.                                

EXAMPLE II Preparation of 2-methyl-4-pentenoic acid

Into a 250 ml flask equipped with magnetic stirrer, the following materials are added:

    Ethyl-2-methyl-4-pentenoate                                                                       80 g                                                        (prepared according to                                                         Example I)                                                                     50% Aqueous NaOH   70 g                                                        Methanol           100 ml                                                 

Over a 4-hour period, the mixture is stirred at 30°-50°C. At the end of the 4-hour period, 200 ml water is added to the reaction mass.

The reaction mass is then extracted with three 200 ml portions of toluene. The aqueous layer is acidified and re-extracted with two 100 ml portions of toluene. The toluene extracts are combined and washed with three 50 ml portions of 20% aqueous NaCl followed by one 40 ml portion of 10% sodium acetate. The reaction product so treated is then evaporated to remove the toluene solvent. It is then fractionally distilled using a semi-micro still at 72°-74°C and 5 mm Hg. pressure.

    NMR Analysis    Interpretation                                                 ______________________________________                                                         O                                                                              ∥                                                     12.00 ppm (s)   --C--O--H      1H                                              6.00-5.60 (m)   HC = CH.sub.2  1H                                              5.18-5.02 (m)   HC = CH.sub.2  2H                                              2.76-2.04 (m)    =C--CH.sub.2 -- +                                                                            3H                                                               Me--CH--C=O                                                   1.19 (d)        CH.sub.3 --CH--C=O                                                                            3H                                              IR Analysis:                                                                    915 cm.sup.-.sup.1                                                             990                                                                           1210                                                                           1240                                                                           1280                                                                           1415                                                                           1430                                                                           1640                                                                           1700                                                                           2660                                                                           2940                                                                           2980                                                                           3080                                                                           ______________________________________                                          The NMR spectrum is illustrated in FIG. 3.                                     The IR spectrum is illustrated in FIG. 4.                                

EXAMPLE III Preparation of isobutyl-2-methyl-4-pentenoate

Into a 500 ml reaction vessel equipped with stirrer, 3 inch splash column and theremometer, the following materials are added:

    Ethyl-2-methyl-4-pentenoate                                                                          56 g                                                     (Produced according to                                                                               (0.4 moles)                                              Example I)                                                                     Isobutyl Alcohol      112 g                                                    p-Toluene sulfonic acid                                                                               0.5 g                                                   Primol                10 g                                                     Ionol (A registered trademark                                                                         0.1 g                                                   for butylated hydroxytoluene                                                   manufactured by the Shell                                                      Chemical Company)                                                         

The reaction mass is heated to 110°C and atmospheric temperature for a period of 10 hours, while distilling off light fractions (head temperature: 45°-83°C). After the 10 -hour period, 72,4 g light fractions are distilled.

Vacuum is then applied and the remaining unreacted isobutyl alcohol is distilled. The residual product is then rushed over yielding a mixture of isobutyl-2-methyl-4-pentenoate and ethyl-2-methyl-4-pentenoate. This mixture is refractionated through a 12 plate Vigreaux column at 95°-96°C and 40 mm Hg pressure yielding isobutyl-2-methyl-4-pentenoate.

The nuclear magnetic resonance analysis is as follows:

    The nuclear magnetic resonance analysis is as follows:                         ppm             Interpretation                                                 ______________________________________                                         0.91 ppm (d)    CH.sub.3                                                                       |                                                                     CH.sub.3 --C-- 6H                                              1.14 ppm (d)    H                                                                              CH.sub.3 --C-- 3H                                              1.92 ppm (m)    Me                                                                             |                                                                     HC--                                                                           |                                                                     Me             1H                                              2.60-2.1 ppm (m)                                                                               =C--CH.sub.2 --                                                                |                                                                     + HC--C--                                                                      |∥                                                           O              3H                                              3.82 ppm (d)    --CH.sub.2 --O--C--                                                            ∥                                                                     O              2H                                                                  |                                                 5.1-4.94            --C=CH.sub.2   2H                                                   AB.sub.2                                                                                  |                                                 5.94-5.54           HC=C--         1H                                          The infra-red analysis is as follows:                                          920 cm.sup.-.sup.1                                                                        1460                                                                990        1470                                                                1140       1730                                                                1180       2940                                                                1380       2960                                                                ______________________________________                                    

Mass spectral data: Parent peak, then in decreasing order of intensity:

m/e= 170/69, 41, 57, 27, 97.

FIG. 9 illustrates the NMR spectrum for isobutyl-2-methyl-4-pentenoate. FIG. 10 illustrates the IR spectrum for isobutyl-2-methyl-4-pentenoate.

EXAMPLE IV Preparation of n-hexyl-2-methyl-4-pentenoate

Into a 250 ml reaction vessel equipped with stirrer, 3 inch splash column and thermometer, the following materials are added:

    Ethyl-2-methyl-4-pentenoate                                                                          56 g                                                     (Prepared according to                                                                               (0.4 moles)                                              Example I)                                                                     n-Hexyl Alcohol       60 g                                                     p-Toluene Sulfonic Acid                                                                               0.4 g                                                   Primol                10 g                                                     Ionol                  0.1 g                                              

The reaction mass is heated to 140°-150°C at atmospheric pressure over a period of 18 hours, while distilling off light fractions. By the end of the 18-hour period, 11.7 g of low boilers is distilled. The residual product is then rushed over, and then fractionated on a 12 plate Vigreaux column at 88°C and 3.9-4.1 mm Hg. pressure to yield the n-hexyl-2-methyl-4-pentenoate.

    The nuclear magnetic resonance analysis is as follows:                         ppm            Interpretation                                                  ______________________________________                                         0.88 ppm (t)   CH.sub.3 --(CH.sub.2).sub.n                                                                     3H                                             1.14 ppm (d)   H                                                                              CH.sub.3 --C--   3H                                                            |                                                      1.70-1.12 ppm (m)                                                                             --CH.sub.2 --    8H                                             2.58-2.04 ppm (m)                                                                             =C--CH.sub.2 -- +                                                                               3H                                                            |                                                                     HC--C--                                                                        |∥                                                           O                                                               4.04 ppm (t)   O                                                                              ∥                                                                     --CH.sub.2 --CH.sub.2 --O--C--                                                                  2H                                                                |                                                  5.10-4.94          HC=CH.sub.2      2H                                                  AB.sub.2                                                                                 |                                                  5.94-5.54          HC=CH.sub.2 --   1H                                         The infra-red analysis is as follows:                                          910 cm.sup.-.sup.1                                                                     1460       2980                                                        980     1730                                                                   1140    2850                                                                   1180    2930                                                                   ______________________________________                                    

mass spectral data: Parent peak, then in decreasing order of intensity:

m/e= 198/69, 41, 43, 27, 114, 29.

FIG. 11 represents the NMR spectrum for n-hexyl-2-methyl-4-pentenoate. FIG. 12 represents the IR spectrum for n-hexyl-2-methyl-4-pentenoate.

EXAMPLE V Strawberry Flavors

The following basic strawberry flavor is prepared:Ingredients Parts by Weight______________________________________p-Hydroxybenzylacetone 2Vanillin 15Maltol 20Ethyl methylphenyl glycidate 15Benzyl acetate 20Ethyl butyrate 10Methyl cinnamate 5Methyl anthranilate 5Alpha-ionone 1Gamma-undecalactone 2Diacetyl 2Anethole 1Cis-3-hexenol 17Ethanol (95% aqueous) 385Propylene glycol 500______________________________________

To one third of this flavor, ethyl-2-methyl-4-pentenoate (prepared according to Example I) is added at the rate of 1%. To another third of this flavor, 2-methyl-4-pentenoic acid (prepared according to Example II) is added at the rate of 8%. The third portion of this flavor is kept "as is". The three flavors thus produced are compared at the rate of 0.005% (50 ppm) in water by a bench panel.

The flavor containing the ethyl-2-methyl-4-pentenoate is found to have a more fresh natural strawberry-like aroma and taste than the basic flavor formulation. The flavor containing the 2-methyl-4-pentenoic acid also was found to have a more natural strawberry-like aroma and taste; especially a preferred, sweet, fresh, strawberry-like aroma, and is preferred over the basic flavor formulation.

EXAMPLE VI

The following concentrate is prepared:

    Ingredient           Percent                                                   ______________________________________                                         Geraniol             1.00                                                      Ethyl methyl phenyl glycidate                                                                       3.50                                                      Isobutyl-2-methyl-4-pentenoate                                                                      5.00                                                      (Prepared according to the process                                             of Example III)                                                                Vanillin             5.50                                                      Ethyl pelargonate    13.00                                                     Isoamyl acetate      14.00                                                     Ethyl butyrate       58.00                                                                          100.00                                                    ______________________________________                                    

EXAMPLE VII

Another concentrate is prepared as follows:

    Ingredient           Percent                                                   ______________________________________                                         Naphthyl ethyl ether 1.0                                                       Vanillin             2.5                                                       Ethyl methyl phenyl glycidate                                                                       3.0                                                       Isobutyl-2-methyl-4-pentenoate                                                                      5.0                                                       (Prepared according to the process                                             of Example III)                                                                Ethyl acetate        9.5                                                       Isoamyl acetate      12.0                                                      Ethyl butyrate       26.0                                                      Isoamyl butyrate     41.0                                                                           100.00                                                    ______________________________________                                    

EXAMPLE VIII

The concentrate prepared in Example VI is dissolved in 4 volumes of propylene glycol and the mixture is added to a hard candy melt at the rate of 1.5 oz. of the concentrate solution per 100 lbs. of melt. After the finished candy has been produced, it is found to have an excellent strawberry flavor. When the candy is compared with candy made under the same conditions, but without the isobutyl-2-methyl-4-pentenoate prepared according to the process of Example III in the concentrate, it is found to have an inferior strawberry flavor.

EXAMPLE IX

The propylene glycol solution of the concentrate as prepared in Example VIII is added to a simple syrup at the rate of 1/8 oz. per gallon of syrup. The syrup is acidified by the addition of 1.5 oz. of 50% aqueous citric acid solution to each gallon of syrup. A carbonated beverage is prepared by admixing 1 oz. of the flavored, acidified syrup with 5 oz. of carbonated water. The beverage so prepared has an excellent fresh strawberry flavor, and is found to be markedly superior to a beverage prepared in the same manner but without the isobutyl-2-methyl-4-pentenoate prepared according to the process of Example III.

EXAMPLE X

The flavor concentrate prepared in Example VII is admixed with gum arabic and in the proportion of 7 lbs. of concentrate to 28 lbs. of gum arabic in 65 lbs. of water, and the aqueous mixture is spray-dried. The flavor concentrate-carrier combination so obtained is then added to a gelatin dessert mix in the ratio of 1oz. of spray-dried material to 100 lbs. of dessert mix powder. The gelatin dessert produced from the mix has an excellent strawberry flavor and is markedly superior to a gelatin dessert prepared in the same manner without the isobutyl-2-methyl-4-pentenoate prepared according to the process of Example III in the concentrate.

EXAMPLE XI Pear Flavor Formulation

The following mixture is prepared:

    Ingredient            Parts by Weight                                          ______________________________________                                         Vanillin              2.0                                                      Ethyl Hexanoate       0.5                                                      Ethyl Decanoate       1.0                                                      Benzyl Acetate        0.5                                                      Ethyl Octanoate       2.0                                                      Gamma Undecalactone (10% in 95%                                                                      2.0                                                      food grade ethyl alcohol)                                                      Alpha Ionone (0.1% in 95% food                                                                       5.0                                                      grade ethanol)                                                                 Hexyl Acetate         25.0                                                     Lemon Oil, cold pressed                                                                              5.0                                                      Ethyl Butyrate        7.0                                                      Ethyl Acetate         40.0                                                     Butyl Acetate         20.0                                                     Amyl Valerate         65.0                                                     Amyl Acetate          640.0                                                    Ethyl Alcohol         185.0                                                    ______________________________________                                    

n-Hexyl-2-methyl-4-pentenoate prepared according to the process of Example IV is added to a first portion of the basic pear formulation at the rate of 5%. Another portion of the basic pear formulation is used "as-is". Both flavor formulations are compared in water at a level of 50 ppm. Both flavors are evaluated by a bench panel of five members. The pear flavor with the addition of the n-hexyl-2-methyl-4-pentenoate is judged by the bench panel as having the notes of the ripe, fresh, Bartlet pear, and is thus preferred against the flavor without the said n-hexyl-2-methyl-4-pentenoate.

EXAMPLE XII A. Powder Flavor

20 Grams of the flavor composition of Example V is emulsified in a solution containing 300 gm gum acacia and 700 gm water. The emulsion is spray-dried with a Bowen Lab Model Drier utilizing 250 c.f.m. of air with an inlet temperature of 500°F., an outlet temperature of 200°F., and a wheel speed of 50,000 r.p.m.

B. The following mixture is prepared:

    Ingredient            Parts by Weight                                          ______________________________________                                         Liquid Flavor Composition                                                                            48.4                                                     of Example V                                                                   Cab-O-Sil M-5         3.2                                                      (Brand of Silica produced by the                                               Cabot Corporation of 125 High Street,                                          Boston, Mass. 02110; Physical                                                  Properties:                                                                    Surface Area: 200 m.sup.2 /gm                                                  Nominal Particle Size: 0.012 microns                                           Density: 2/3 lbs/cu.ft.)                                                       ______________________________________                                    

The Cab-O-Sil is dispersed in the liquid flavor composition of Example V with vigorous stirring, thereby resulting in a viscous liquid. 48.4 Parts by weight of the powder flavor composition prepared in Part A is then blended into the said viscous liquid, with stirring at 25°C for a period of 30 minutes, resulting in a thixotropic sustained release flavor paste.

EXAMPLE XIII Chewing Gum

100 parts by weight of chicle are mixed with 4 parts by weight of the flavor prepared in accordance with Example XII. 300 parts of sucrose and 100 parts of corn syrup are added. Mixing is effected in a ribbon blender with jacketed side walls of the type manufactured by the Baker Perkins Co.

The resultant chewing gum blend is then manufactured into strips 1 inch in width and 0.1 inches in thickness. The strips are cut into lengths of 3 inches each. On chewing the chewing gum has a pleasant long lasting strawberry flavor.

EXAMPLE XIV Toothpaste Formulation

The following separate groups of ingredients are prepared:

    Group "A"                                                                      30.200    Glycerin                                                             15.325    Distilled Water                                                       .100     Sodium Benzoate                                                       .125     Saccbarin Sodium                                                      .400     Stannous Fluoride                                                    Group "B"                                                                      12.500    Calcium Carbonate                                                    37.200    Dicalcium Phosphate (Dihydrate)                                      Group "C"                                                                      2.000     Sodium N-Lauroyl Sarcosinate (foaming agent)                         Group "D"                                                                      1.200     Flavor Material of Example XII                                       100.00 (Total)                                                                 PROCEDURE:                                                                     1.   The ingredients in Group "A" are stirred and heated in a                       steam jacketed kettle to 160°F.                                    2.   Stirring is continued for an additional three to five                          minutes to form a homogenous gel.                                         3.   The powders of Group "B" are added to the gel, while                           mixing until a homogenous paste is formed                                 4.   With stirring, the flavor of "D" is added and lastly the                       sodium n-lauroyl sarcosinate.                                             5.   The resultant slurry is then blended for one hour. The                         completed paste is then transferred to a three roller                          mill and then homogenized, and finally tubed.                        

The resulting toothpaste when used in a normal tooth-brushing procedure yields a pleasant strawberry flavor, of constant strong intensity throughout said procedure (1-1.5 minutes).

EXAMPLE XV Chewable Vitamin Tablets

The flavor material produced according to the process of Example XII is added to a Chewable Vitamin Tablet Formulation at a rate of 5 gm/gm which Chewable Vitamin Tablet Formulation is prepared as follows:

                                 Gms/1000 tablets                                  __________________________________________________________________________     Vitamin C (ascorbic acid)                                                      as ascorbic acid-sodium ascorbate mixture 1:1                                                               70.0                                              Vitamin B.sub.1 (thismine mononitrate)                                         as Rocoat thiamine mononitrate 331/3%(Hoffman La Roche)                                                     4.0                                               Vitamin B.sub.2 (riboflavin)                                                   as Rocoat riboflavin 331/3%  5.0                                               Vitamin B.sub.6 (pyridoxine hydrochloride)                                     as Rocoat pyridoxine hydrochloride 31/3%                                                                    4.0                                               Niacinamide                                                                    as Rocoat niacinamide 331/3% 33.0                                              Calcium pantothenate         11.5                                              Vitamin B.sub.12 (cyanocobalamin)                                              as Merk 0.1% in gelatin      3.5                                               Vitamin E (dl-alpha tocopheryl acetate                                         as dry Vitamin E acetate 331/3% Roche                                                                       6.6                                               d-Biotin                     0.044                                             Certified lake color         5.0                                               Flavor of Example XII        5.0                                               Sweetener - sodium saccharin 1.0                                               Magnesium stearate lubricant 10.0                                              Mannitol q.s. to make        500.0                                             __________________________________________________________________________

Preliminary tablets are prepared by slugging with flat-faced punches and grinding the slugs to 14 mesh. 13.5 g dry Vitamin A Acetate and 0.6 Vitamin D are then added as beadlets. The entire blend is then compressed using concave punches at 0.5 g each.

Chewing of the resultant tablet yields a pleasant, long-lasting, consistently strong strawberry flavor for a period of 12 minutes.

EXAMPLE XVI Preparation of ethyl-2-methyl-3,4-pentadienoate

Reaction: ##SPC9##

Into a 2 liter autoclave, the following materials are placed:

    Ingredient           Parts by Weight                                           ______________________________________                                         Triethyl orthopropionate                                                                            495 grams                                                 2-Propyn-1-ol         90 grams                                                 Propionic acid        12 grams                                                 ______________________________________                                    

The autoclave is closed and the reaction mass is heated to 150°C (over a period of 50 minutes). The reaction mass is then maintained at a temperature of between 135°-160°C and at a pressure of 20 up to 60 psig for a period of 3 hours. At the end of this 3-hour period, the autoclave is opened and the reaction mass is cooled to room temperature. 12.6 g of sodium bicarbonate is then added to the reaction mass in order to neutralize the propionic acid. 30 g of Primol (see Note 1) and 0.1 g of Ionol (see Note 2 ) are added and the resulting reaction product is fractionally distilled at atmospheric pressure to a pot temperature of 129°C. A mixture of ethanol and ethyl propionate is distilled over. Vacuum is then applied to the distillation column and the resultant product, ethyl-2-methyl-3,4-pentadienoate is distilled at a vapor temperature of 65°-69°C at a pressure of 24-33 mm Hg as fractions 5-10 of the following fractions:

    Fraction                                                                              Vapor     Liquid    Pressure                                                                              Weight of                                                                             Reflux                                No.    Temp.     Temp.     (mm Hg)                                                                               Fraction                                                                              Ratio                                 ______________________________________                                         1       68-72°C                                                                           127-87°C                                                                         760    174.5 g                                                                               9:1                                   2      28-42     86-83     48-50  19.4   9:1                                   3      69        84        45     12.6   9:1                                   4      65        79        34     20.1   9:1                                   5      67        80        33     38.9   4:1                                   6      67        82        33     32.5   4:1                                   7      67        82        33     36.8   4:1                                   8      67        83        33     37.2   4:1                                   9      66        84        24     39.8   4:1                                   10     65        94        24     36.9   4:1                                   11     57        108       10     45.5   4:1                                   12     39        172       2.3    14.5   4:1                                   ______________________________________                                    

The resulting material is confirmed by IR, NMR and mass spectral analyses to have the structure: ##SPC10##

Mass spectral analysis:

Parent Peak, then in order of decreasing intensity: m/e = 140(M⁺); 67, 97, 29, 41, 125

    Nuclear Magnetic Resonance Analysis:                                           ppm        Interpretation                                                      ______________________________________                                         1.26 (t)   CH.sub.3 --C--O--C--                                                                              6H                                                          ∥                                                                     O                                                                   1.28 (d)   CH.sub.3 --C--C--  6H                                                          ∥                                                                     O                                                                   3.10 (m)   =C--CH--C=O        1H                                               4.12 (q)   CH.sub.3 --CH.sub.2 --O--C--                                                                      2H                                                          ∥                                                                     O                                                                   4.76 (m)   H.sub.2 C=C=C--    2H                                               5.40 (m)   C=C=CH             1H                                               ______________________________________                                    

The nuclear magnetic resonance spectrum is set forth in FIG. 5.

Infra Red Analysis:

Peaks

850 cm⁻ ¹

1050

1175

1225

1375

1425

1730

1950

2880

2925

2975

The infra-red spectrum is set forth in FIG. 6.

At a concentration of 0.5 ppm, the resulting product ethyl-2-methyl-3,4-pentadienoate has a fruity, strawberry, creamy aroma with berry, apple and pineapple notes and a sweet, fruity, strawberry flavor with woody and creamy nuances.

Note 1

Primol is a registered trademark identifying a hydrocarbon mineral oil produced by Exxon Corp. of Linden, New Jersey.

Note 2

Ionol is a registered trademark identifying the compound 2,6-di-t-butyl-4-methyl phenol.

EXAMPLE XVII Hydrogenation of ethyl-2-methyl-3,4-pentadienoate Using a Lindlar Catalyst, Thereby Preparing Mixtures of ethyl-2-methyl-cis-3-pentenoate and ethyl-2-methyl-4-pentenoate

Reaction: ##SPC11##

Into a 2-liter autoclave, the following ingredients are placed:

    Ingredient             Quantity                                                ______________________________________                                         Ethyl-2-methyl-3,4-pentadienoate                                                                      577.8 grams                                             produced according to the process                                              of Example XVI                                                                 5% Palladium on calcium carbonate                                                                      1.4 grams                                              catalyst (Lindlar catalyst)                                                    ______________________________________                                    

The autoclave is connected by means of pressure tubing to a hydrogen containing cylinder. The autoclave is then sealed and while adding hydrogen into the autoclave from the hydrogen containing cylinder and maintaining the pressure within the autoclave at 60 pounds per square inch gauge the reaction mass is stirred. During the hydrogenation and over a 19-hour period, the reaction mass is maintained at room temperature by means of the application of cooling. At the end of the 19-hour period, the autoclave is opened; and an additional 1.4 grams of Lindlar catalyst is added. The autoclave is then closed and hydrogen is continuously added thereto while stirring the reaction mass over an additional reaction period of 10 hours. At the end of the 10-hour period, the autoclave is opened, and the reaction mass is filtered. An additional 2.8 grams Lindlar catalyst is then added to the reaction mass which is then again placed in the autoclave with hydrogen being added thereto and pressure being maintained at 60 pounds per square inch gauge. At the end of one and three-quarter hours, GLC analysis indicates that the reaction is completed. The GLC diagram is set forth in FIG. 7. The autoclave is then opened and the reaction mass is filtered. The filtered reaction mass is then distilled on a 1 inch × 1 foot Goodloe distillation column after adding thereto 10 grams of Primol (see note 1) and 0.1 grams of Ionol (see note 2) yielding the following fractions.

                       Vacuum  Weight                                              Fraction                                                                            Vapor  Liquid (mm Hg  of    Reflux                                        No.  Temp.  Temp.  Pressure)                                                                              Fraction                                                                             Ratio                                         __________________________________________________________________________     1     31-33°C                                                                        77-86°C                                                                       200.0-205.0                                                                            18.2 g                                                                               19:1                                          2    60     90     200.0   17.0  19:1                                          3    61     93     200.0   11.0  19:1                                          4    62     97     200.0   12.6  19:1                                          5    62     100    200.0   13.6  19:1                                          6    62     107    200.0   13.5  19:1                                          7    62     111    200.0   14.3  19:1                                          8    65     115    200.0   12.5  19:1                                          9    81     119    200.0   13.1  19:1                                          10    88-110                                                                               116-117                                                                               205     6.6   19:1                                          11   112    117    205     6.0   19:1                                          12   113    117    205     6.2   19:1                                          13   113    118    205     7.0   19:1                                          14   114    118    205     4.5   19:1                                          15   114    118    205     17.8   9:1                                          16   114    118    205     21.5   9:1                                          17   114    118    205     23.9   9:1                                          18   114    118    205     21.2   9:1                                          19   115    120    205     24.5   9:1                                          20   115    120    205     23.2   9:1                                          21   115    120    205     10.0   9:1                                          22   114-115                                                                               119-120                                                                               200-205 20.8   9:1                                          23   115    121    205     20.8    9:1                                         24   115    121    205     15.0   9:1                                          25   115    122    205     19.3   9:1                                          26   115    124    205     17.9   9:1                                          27   116    125    205     21.9   9:1                                          28   116    128    205     18.9   9:1                                          29   116    131    205     19.0   4:1                                          30   116    144    205     24.6   4:1                                          31   116    160    205     13.5   4:1                                          32   111    200    205     6.1    4:1                                          __________________________________________________________________________

Fractions 12, 13, 14, 21, 23 and 31 are analyzed using GLC analysis (conditions: 10 foot × 1/4 inch Carbowax 20M column programmed at 120°-150°C).Fraction Weight Percentage of ethyl-2- Percentage of ethyl-No. of methyl-cis-3- 2-methyl-4- Fraction pentenoate pentenoate______________________________________12 6.2 g 57.6% 41.6%13 7.0 g 59.2% 38.9%21 10.0 g 70.9% 28.7%23 20.8 g 75.6% 24.1%31 13.5 g 93.8% 4.9%______________________________________

Analyses

a. Ethyl-2-methyl-cis-3-pentenoate

i. Mass Spectral Analysis: Parent Peak; then in decreasing order of intensity: m/e = 142(M⁺); 69, 41, 29, 27, 39, 68.

    (ii) NMR Analysis:                                                             ppm              Interpretation                                                ______________________________________                                                          CH.sub.3                                                                       |                                                    1.18 (d)         =C--C--C=O                                                    1.22 (t)         CH.sub.3 --C--O                                               1.64 (d)         =C--CH.sub.3                                                                   H                                                             3.40 (m)         =C--C--C=O                                                                     O                                                                              ∥                                                    4.10 (g)         --CH.sub.2 --O--C--                                           5.20 (m)         HC=CH                                                         ______________________________________                                    

Infrared Analysis:

710, 860, 960, 1020, 1045, 1090, 1140, 1175, 1240, 1325, 1370, 1395, 1450, 1650, 1730, 2880, 2900, 2940, 2980, 3020 cm⁻ ¹

b. ethyl-2-methyl-4-pentenoate

Mass Spectral Analysis: Parent Peak then in decreasing order of intensity: m/e = 142(M⁺); 69, 41, 29, 27, 39, 68.

    NMR Analysis:                                                                  ppm             Interpretation                                                 ______________________________________                                                         H                                                              1.16 ppm (d)    CH.sub.3 --C--C--                                                              ∥                                                                     O                                                                                             6H                                              1.20 (t)        CH.sub.3 --CH.sub.2 --O--C--                                                   ∥                                                                     O                                                              2.64-2.08 (m)   =C--CH.sub.2 + HC--                                                                           3H                                                              ∥                                                                     O                                                              4.12 (q)        Me--CH.sub.2 --O--C--                                                                         2H                                                              ∥                                                                     O                                                              5.18-4.98 (m)   HC=CH.sub.2    2H                                              5.98-5.56 (m)   HC=CH.sub.2    1H                                              ______________________________________                                    

Infrared Analysis:

710, 860, 960, 1020, 1045, 1090, 1140, 1175, 1240, 1325, 1370, 1395, 1450, 1650, 1730, 2880, 2900, 2940, 2980, 3020 cm⁻ ¹

Note 1

Primol is a registered trademark identifying a hydrocarbon mineral oil produced by Exxon Incorporation of Linden, New Jersey.

Note 2

Ionol is a registered trademark identifying the compound 2,6-di-tert-butyl-4-methyl-phenol.

EXAMPLE XVIII Hydrogenation of ethyl-2-methyl-3,4-pentadienoate Using a 5% Palladium on Carbon Catalyst

Reaction: ##SPC12##

Into a 250 cc Parr Bomb the following ingredients are placed:

    Ingredient             Amount                                                  ______________________________________                                         Ethyl-2-methyl-3,4-pentadienoate                                                                      25 grams                                                produced according to the process                                              of Example XVI                                                                 5% Palladium on Carbon 0.025 grams                                             ______________________________________                                    

The Parr Bomb is connected by means of pressure tubing to a hydrogen-containing cylinder. The Parr Bomb is then sealed while adding hydrogen thereinto from the hydrogen-containing cylinder and maintaining pressure within the Parr Bomb at 25-50 psig. The reaction is maintained at room temperature using external cooling. After a period of 3.5 hours, the Parr Bomb is opened and the contents are filtered. GLC analysis indicates that the reaction is complete. GLC Analysis (Conditions: 8 foot × 1/2 inch carbowax column; column temperature 120°C) indicates presence of the following components in the following weight percentages:

    Component              Weight Percent                                          ______________________________________                                         Ethyl-2-methyl-cis-3-  65.7%                                                   pentenoate                                                                     Ethyl-2-methyl-4-      14.3%                                                   pentenoate                                                                     Ethyl-2-methyl pentanoate                                                                             19.9%                                                   ______________________________________                                    

The GLC diagram is set forth in FIG. 8.

BRIEF SUMMARY OF THE DRAWINGS

FIG. 1 is an illustration of the NMR spectrum of ethyl-2-methyl-4-pentenoate, produced according to Example I.

FIG. 2 is an illustration of the infrared spectrum of ethyl-2-methyl-4-pentenoate produced according to Example I.

FIG. 3 is an illustration of the NMR spectrum of 2-methyl-4-pentenoic acid, produced according to Example II.

FIG. 4 is an illustration of the infrared spectrum of 2-methyl-4-pentenoic acid produced according to Example II.

FIG. 5 is an illustration of the NMR spectrum of ethyl-2-methyl-3,4-pentadienoate produced according to Example XVI (distillation fraction 10).

FIG. 6 is an illustration of the infrared spectrum for ethyl-2-methyl-3,4-pentadienoate produced according to Example XVI (distillation fraction 10).

FIG. 7 is an illustration of the GLC curve for a mixture of ethyl-2-methyl-4-pentenoate and ethyl-2-methyl-cis-3-pentenoate produced by the hydrogenation of ethyl-2-methyl-3,4-pentadienoate with a Pd/CaCO₃ catalyst according to Example XVII.

FIG. 8 is an illustration of the GLC curve for a mixture of ethyl-2-methyl-4-pentenoate, ethyl-2-methyl-cis-3-pentenoate and ethyl-2-methyl-pentanoate produced according to Example XVIII.

FIG. 9 is an illustration of the NMR spectrum for isobutyl-2-methyl-4-pentenoate produced according to Example III.

FIG. 10 is an illustration of the infrared spectrum for isobutyl-2-methyl-4-pentenoate produced according to Example III.

FIG. 11 is an illustration of the NMR spectrum for n-hexyl-2-methyl-4-pentenoate produced according to Example IV.

FIG. 12 is an illustration of the infrared spectrum for n-hexyl-2-methyl-4-pentenoate produced according to Example IV. 

What is claimed is:
 1. A process for altering the organoleptic properties of a consumable material selected from the group consisting of food flavoring compositions, foodstuffs, and chewing gum which comprises adding thereto a small but effective amount of a composition comprising an unsaturated ester having the structure: ##SPC13##wherein R is one of C₂ -C₆ alkyl in order to enhance or impart a fruit flavor in said consumable material.
 2. A process according to claim 1 wherein the consumable material is a foodstuff.
 3. A process according to claim 1 wherein the consumable material is a food flavor.
 4. A flavor modifying composition comprising from about 0.25% up to about 15% based on the total weight of the composition of a compound having the structure: ##SPC14##wherein R is one of C₂ -C₆ alkyl and the remainder being a flavor adjuvant, which is a compound selected from the group consisting of p-hydroxybenzyl acetone, maltol, benzyl acetate, methyl cinnamate, geraniol, ethyl methyl phenyl glycidate, vanillin, methyl anthranilate, alpha ionone, gamma undecalactone, ethyl pelargonate, isoamyl acetate, ethyl butyrate, diacetyl, anethole, cis-3-hexenol-1, naphthyl ethyl ether, ethyl acetate, isoamyl butyrate, 2-methyl-2-pentenoic acid, 4-allyl-1,2,6-trimethoxy benzene and 4-propenyl-1,2,6-trimethoxy benzene.
 5. The process of claim 1 wherein the moiety R in the unsaturated ester is selected from the group consisting of ethyl, hexyl and isobutyl. 